// Ninf-G-XX, ver. 0.1
// Copyright 2011 National Institute of Advanced Industrial Science and Technology
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef __INPUT_STREAM_H__
#define __INPUT_STREAM_H__

namespace ninf {
	namespace lib {

		/** 
		 *  abstract base class for input streams
		 */
		class InputStream {
		public:
			virtual ~InputStream(){};
			
			/**
			 * read a single byte 
			 * if it encounters EOF returns -1
			 * if it encounters some error throws exception
			 */
			virtual int read() = 0;
			
			/*
			 * read byte array and stores it to val 
			 * it returns number of actually read bytes
			 */ 
			virtual int read(char * val, int offset, int len) = 0;
			
			
			/*
			 * read byte array and stores it to val 
			 * keep tring to read specified length
			 * returns non 0 if succuess, 0 if failed
			 */ 
			virtual int readFully(char * val, int offset, int len) = 0;
			
			
			/*
			 * close underlying stream
			 */ 
			virtual void close() = 0;
			
		};
	}
}

#endif
